King's Gambit Accepted

also known as: KGA

1. e4 e5 2. f4 exf4

Named after

Not an eponym — Black accepts the offered f-pawn, as three centuries of etiquette demanded.

Origin

The main battlefield of chess from the 16th to the mid-19th century; whole families of named sub-gambits (Muzio, Kieseritzky, Allgaier…) live here.

The story

Taking the pawn is principled: Black grabs material and dares White to prove the attack. The resulting theory is a museum of romantic-era violence — in the Muzio Gambit White sacrifices a full knight on move five for nothing but open lines, and analysis says it is nearly sound. Every named line records a 19th-century personality: Kieseritzky the café professional, Allgaier the Viennese theorist whose knight sacrifice on f7 still wins miniatures two centuries on.

Why it matters

The KGA is chess's laboratory of initiative: it taught the game that time and open lines can outweigh material — the insight underneath every sacrifice since.

Notable games

• Anderssen–Kieseritzky, London 1851
• Short–Kasparov, London blitz 1993 (a modern KGA massacre)